1. Field of the Invention
The invention relates to a plug-in connector including a receptacle and a plug, especially for hose connections for use in motor vehicles. In particular, the present invention relates to such a plug-in connector where the receptacle is provided with an insertion opening for the plug and at least one locking spring which is used to lock the receptacle and plug. The present invention also relates to such a plug-in connector where the locking spring is provided with at least one locking section and one unlocking section which can be actuated from the outside of the receptacle.
2. Description of the Related Art
The plug-in connector in accordance with the present invention may be generally used for hose connections, i.e. for connecting the ends of two hoses. But the utility of the plug-in connector in accordance with the present invention is not limited to such an application. On the one hand, the plug-in connector in accordance with the present invention can also be used for pipe connections such as in the case when relatively flexible pipes are to be connected. On the other hand, the present invention may be practiced in other applications where either the receptacle or the plug is made stationary or provided on a stationary fixture and the complementary component (either a plug or a receptacle) is provided on an end of a hose or a pipe such that the hose or the pipe may be connected with the stationary receptacle or plug. In this regard, although the plug-in connector in accordance with the present invention is described in detail in the context of plug-in connector for hose connection applications, it should be understood that the present invention is not limited thereto.
A plug-in connector of the initially described type is generally known and practiced in the art. In these known plug-in connectors, a spring wire which is bent in roughly a U-shape is seated from the outside on the receptacle or is inserted into the receptacle for locking and unlocking purposes. In the area of the insertion opening, the receptacle is provided with through slots on opposite sides. Inserted into these slots, the arms of the U-shaped spring wire partially project into the insertion opening of the receptacle, specifically with one locking section at a time. The plug, on its front end is provided with a contact bevel which, when the plug is inserted into the insertion opening of the receptacle, presses the two arms of the U-shaped spring wire to the outside. As the plug continues to be inserted into the insertion opening of the receptacle, the locking sections of the two arms of the U-shaped spring wire fit behind a corresponding stop on the plug. Thus, in this manner, the U-shaped spring wire acts as a locking spring. The U-shaped spring wire described above, is bent in the manner of a loop to the outside on its U-bridge so that in this way, an actuation opening is formed between the receptacle and the U-bridge which has been made looped. On the outside of the receptacle, guide surfaces which are limited by one stop each, are assigned to the ends of the two arms of the U-shaped spring wire. For unlocking purposes, an unlocking tool, for example, a screwdriver, is inserted into the above described actuation opening and the U-shaped spring wire is pressed or pulled radially to the outside. In so doing, the locking sections of the legs of the U-shaped spring wire move to the outside so that these locking sections disengage from the stop provided on the plug. The stops which border the guide surfaces on the receptacle are designed to prevent the locking spring (i.e. the U-shaped spring wire) from being completely withdrawn from the receptacle during unlocking.
In the above described known plug-in connector, one disadvantage is that during unlocking, it can happen that the locking spring can be unintentionally withdrawn from the receptacle and lost, in spite of the stops which border the guide surfaces on the receptacle. When this occurs, a new locking spring must be procured first in order to again, lock the receptacle and plug. In addition, another disadvantage of the known plug-in connector is that the locking spring can be bent. When this occurs, it must then be moved again into its original position for locking by hand. Yet another disadvantage is that one can easily unintentionally unlock the prior art plug-in connector by hand. Such unintentional unlocking can be very dangerous and poses a very significant safety concern. For example, such unintentional unlocking can lead to scalding and severe bums on an unsuspecting person if the plug-in connector is being used to carry a hot medium.